243121320731045 has 4 divisors (see below), whose sum is σ = 291745584877260. Its totient is φ = 194497056584832.

The previous prime is 243121320730963. The next prime is 243121320731063. The reversal of 243121320731045 is 540137023121342.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 188461663121956 + 54659657609089 = 13728134^2 + 7393217^2 .

It is a cyclic number.

It is not a de Polignac number, because 243121320731045 - 2¹⁰ = 243121320730021 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24312132073100 + ... + 24312132073109.

It is an arithmetic number, because the mean of its divisors is an integer number (72936396219315).

Almost surely, 2^{243121320731045} is an apocalyptic number.

It is an amenable number.

243121320731045 is a deficient number, since it is larger than the sum of its proper divisors (48624264146215).

243121320731045 is an equidigital number, since it uses as much as digits as its factorization.

243121320731045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48624264146214.

The product of its (nonzero) digits is 120960, while the sum is 38.

Adding to 243121320731045 its reverse (540137023121342), we get a palindrome (783258343852387).

The spelling of 243121320731045 in words is "two hundred forty-three trillion, one hundred twenty-one billion, three hundred twenty million, seven hundred thirty-one thousand, forty-five".